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Siege Engines




Siege engines are large weapons, temporary structures, or pieces of equipment traditionally used in besieging castles or fortresses.

Table: Siege Engines
Item Cost Damage Critical Range Increment Typical Crew Source
Catapult, heavy 800 gp 6d6 200 ft. (100 ft. minimum) 4 PRG:CRB
Catapult, light 550 gp 4d6 150 ft. (100 ft. minimum) 2 PRG:CRB
Ballista 500 gp 3d8 19–20 120 ft. 1 PRG:CRB
Ram 1,000 gp 3d6* 10 PRG:CRB
Siege tower 2,000 gp 20 PRG:CRB
* See description for special rules.
Table: Catapult Attack Modifiers
Condition Modifier
No line of sight to target square –6
Successive shots (crew can see where most recent misses landed) Cumulative +2 per previous miss (maximum +10)
Successive shots (crew can’t see where most recent misses landed, but observer is providing feedback) Cumulative +1 per previous miss (maximum +5)

Siege engines are treated as difficult devices if someone tries to disable them using Disable Device. This takes 2d4 rounds and requires a DC 20 disable Device check. Siege engines are typically made out of wood and have an AC of 3 (–5 Dex, –2 size), a Hardness of 5, and 80 hit points. Siege engines made up of a different material might have different values. Some siege engines are armored as well. Treat the siege engine as a Huge creature to determine the cost of such armor. Siege engines can be crafted as masterwork and enchanted as magic weapons, adding bonuses on attack rolls to the checks made to hit with the siege engine. A masterwork siege engine costs 300 gp more than the listed price. Enchanting a siege engine costs twice the normal amount. For example, a +1 flaming heavy catapult, armored with full plate, would have an AC of 11 and would cost 23,100 gp (800 gp base + 6,000 gp for the armor + 300 gp masterwork + 16,000 gp for the enhancements).

Ballista: A ballista is essentially a Huge heavy crossbow fixed in place. Its size makes it hard for most creatures to aim it. Thus, a Medium creature takes a –4 penalty on attack rolls when using a ballista, and a Small creature takes a –6 penalty. It takes a creature smaller than Large two full-round actions to reload the ballista after firing.

A ballista takes up a space 5 feet across.

Catapult, Heavy: A heavy catapult is a massive engine capable of throwing rocks or heavy objects with great force. Because the catapult throws its payload in a high arc, it can hit squares out of its line of sight. To fire a heavy catapult, the crew chief makes a special check against DC 15 using only his base attack bonus, Intelligence modifier, range increment penalty, and the appropriate modifiers from the lower section of Table: Siege Engines. If the check succeeds, the catapult stone hits the square the catapult was aimed at, dealing the indicated damage to any object or character in the square. Characters who succeed on a DC 15 Reflex save take half damage. Once a catapult stone hits a square, subsequent shots hit the same square unless the catapult is reaimed or the wind changes direction or speed.

If a catapult stone misses, roll 1d8 to determine where it lands. This determines the misdirection of the throw, with 1 being back toward the catapult and 2 through 8 counting clockwise around the target square. Finally, count 1d4 squares away from the target square for every range increment of the attack.

Loading a catapult requires a series of full-round actions. It takes a DC 15 strength check to winch the throwing arm down; most catapults have wheels to allow up to two crew members to use the aid another action, assisting the main winch operator. A DC 15 Profession (siege engineer) check latches the arm into place, and then another DC 15 Profession (siege engineer) check loads the catapult ammunition. It takes four full-round actions to reaim a heavy catapult (multiple crew members can perform these full-round actions in the same round, so it would take a crew of four only 1 round to reaim the catapult).

A heavy catapult takes up a space 15 feet across.

Catapult, Light: This is a smaller, lighter version of the heavy catapult. It functions as the heavy catapult, except that it takes a DC 10 Strength check to winch the arm into place, and only two full-round actions are required to reaim the catapult.

A light catapult takes up a space 10 feet across.

Ram: This heavy pole is sometimes suspended from a movable scaffold that allows the crew to swing it back and forth against objects. As a full-round action, the character closest to the front of the ram makes an attack roll against the AC of the construction, applying the –4 penalty for lack of proficiency. It’s not possible to be proficient with this device. In addition to the damage given on Table: Siege Engines, up to nine other characters holding the ram can add their Strength modifiers to the ram’s damage, if they devote an attack action to doing so. It takes at least one Huge or larger creature, two Large creatures, four Medium creatures, or eight Small creatures to swing a ram.

A ram is typically 30 feet long. In a battle, the creatures wielding the ram stand in two adjacent columns of equal length, with the ram between them.

Siege Tower: This device is a massive wooden tower on wheels or rollers that can be rolled up against a wall to allow attackers to scale the tower and thus get to the top of the wall with cover. The wooden walls are usually 1 foot thick.

A typical siege tower takes up a space 15 feet across. The creatures inside push it at a base land speed of 10 feet (and a siege tower can’t run). The eight creatures pushing on the ground floor have total cover, and those on higher floors get improved cover and can fire through arrow slits.

Additional Siege Engine Information

Source PRG:UC

All siege engines are at least size Large devices and often much larger. Unless stated otherwise in an individual siege engine description, all siege engines use the following rules.

Proficiency: Siege engines are exotic weapons. A creature with the Siege Engineer feat is proficient with all siege engines, including siege firearms. A creature that is proficient in firearms is also proficient in siege firearms, but not other siege engines.

Crew: The sheer size of a siege engine often necessitates a crew for its use. One person of that crew is the crew leader. Usually the crew leader targets or controls the movement of a siege engine; sometimes the crew leader does both. Often the crew leader is required to take actions and make specific checks in order for a siege engine to function. The rest of the crew members are required to spend actions and make checks in order for a siege engine to function.

The number of members in a crew assumes Medium creatures. A ram can be crewed by Small creatures, but it takes double the crew to do the same job. If Large or larger creatures serve as crew members, each Large creature counts as four crew members, a Huge creature counts as eight Medium creatures, a colossal creature counts as 16 Medium creatures, and a gargantuan creature counts as 20 Medium creatures.

Magical and Masterwork Siege Engines: Siege engines can be masterwork, increasing their Craft DC by 5 and costing an additional 300 gp. A masterwork siege engine can be enchanted at twice the cost for a normal magical weapon. The enhancement bonus of a siege engine applies on attack rolls and targeting checks (in the case of indirect ranged siege engines), and in the case of magical siege engines, the enhancement bonus also applies on damage rolls.

Defense and Hit Points: All siege engines are objects. A siege engine has a Dexterity of 0 (–5 penalty) and a further penalty based on its size. Each type of siege engine has its own hardness and hit points. Siege engines can be armored—treat the siege engine as a creature of its size to determine the cost of the armor. Masterwork siege engine armor can be enchanted for twice the normal cost to enchant armor. Armored siege engines have an armor bonus equal to that normally granted by the specific armor (shields have no effect on a siege engine), a hardness and hit points equal to that of the armor, and bonus hit points equal to the armor bonus × 5.

Moving Siege Engines: Siege engines have a speed. The speed of a siege engine is the distance it can be moved if its full crew makes a move action to move it. Some siege engines have a speed of 0. If this is the case, the engine must be dissembled before movement is possible, or else mounted on a vehicle. Siege engines that are atop or mounted on vehicles move with those vehicles.

Ranged Attacks: Unlike normal ranged weapons, siege engines do not deal half damage when attacking objects.

Critical Hits: When a direct-fire siege engine or a close assault siege engine scores a critical hit, it confirms the critical and deals critical hit damage just like any other weapon. If an indirect-fire ranged siege engine rolls a natural 20 on its targeting check, it can also score a critical hit. The crew leader must reroll the targeting check to confirm the critical. If the confirmation targeting check is successful, the attack is a critical hit, and the siege engine multiplies its damage by its critical multiplier. Unlike normal attacks, siege engines attacks can deal critical hit damage to objects. Siege engines do not gain the benefit of Critical Feats the crew or the crew leader may have.

Mishaps and Misfires: Rolling a natural 1 on an attack roll or a targeting check made by an indirect-fire ranged siege engine produces a mishap. Usually a mishap applies the broken condition. A non-firearm siege engine with the broken condition takes a –2 penalty on attack rolls, targeting checks, and damage rolls. It also moves at half its normal speed. If the creature that serves as crew leader has the Siege Engineer feat, that creature does not generate a mishap on a natural 1 when firing the siege engine. Firearm siege weapons do not gain a mishap on a natural 1, but instead have a misfire value, like other firearms do. An attack roll or targeting check that falls within the misfire range causes the firearm siege engine to misfire. A misfire always misses, and applies the broken condition to the siege engine firearm. A firearm siege weapon with the broken condition takes all of the penalties and limitations that non-firearm siege engines do, and the misfire range of the firearm siege engine is increased by 4. If the firearm siege engine already has the broken condition when it misfires, it explodes. When a firearm siege engine explodes, it deals its damage to all creatures within a blast range (those within the blast can attempt a DC 20 Reflex save for half damage). The normal misfire range of a firearm siege engine and its blast range are given in the individual firearm siege engine description. Crew leaders with the Siege Engineer feat do not lower the misfire value of firearm siege engines.

Constructing and Repairing Siege Engines: A siege engine is a complex device requiring a DC 20 Craft (siege engine) skill check to build or repair.

Disabling Siege Engines: A siege engine is considered a difficult device to disable, requiring 2d4 rounds of effort and a DC 20 Disable Device check to do so. When a siege engine is disabled, it either doesn’t work or is sabotaged and stops working 1d4 minutes after use. Fixing a disabled siege engine requires a DC 20 Craft (siege engine), Disable Device, or Knowledge (engineering) check. It takes 10 minutes to fix the device, and the check can be retried if the fix fails.

Assembling Siege Engines: Siege engines are broken down for transport and can be reassembled on the battlefield, requiring the time and number of workers noted below. Each assembly worker must make a DC 10 Craft (siege engine) check; if untrained, they may not take 10. Assembly can be performed with at least half the required number of workers by doubling the time required. If fewer than half are available, the weapon cannot be assembled.

Table: Siege Engine Assembly
Engine Size Time Required Workers Required
Small 1 minute 1
Medium 10 minutes 2
Large 1 hour 4
Huge 2 hours 6
Gargantuan 4 hours 8
Colossal 8 hours 12

Siege Engine Qualities

The following are the various entries on the equipment tables for siege engines (given in the column headings on Tables: Ranged Siege Engines and Close Assault Siege Engines). While ranged siege engines use most of these entries, close-assault siege engines only use some of them.

Cost: This value is the siege engine’s cost in gold pieces (gp). The cost includes gear needed to work the engine as well as gear for upkeep. Typical ammunition costs and weights are given in siege weapon description.

Damage: This column gives the damage typically dealt by the engine. If the engine has a special mode of attack or damage, this space is marked by the words “see description.” If the siege engine does not deal any damage, but rather is a tool for getting close to or over fortifications, this entry features a dash (—). Some ranged siege engines can be loaded with special ammunition that affects or overrides the weapon’s typical damage or range. As large and imprecise weapons, siege engines do not deal sneak attack damage or any other kind of precision damage.

Critical: The entry for this column notes how the engine is used with the rules for critical hits. Unlike normal ranged weapons, siege engines can deal critical damage to objects as well as creatures.

Range: Any attack at more than the distance listed in this entry is penalized for range. Beyond this range, the attack or targeting check takes a cumulative –2 penalty for each full range increment (or fraction thereof ) of distance to the target. Some siege engines have a minimum range for effectiveness. If that is the case, the range of this weapon is followed by a parenthetical with the minimum range, followed by the abbreviation “min.”

Type: Like weapons, siege engines that deal damage are classified according to the type of damage they deal: B for bludgeoning, P for piercing, or S for slashing. Some engines deal damage of multiple types. Some special siege engines (like the firedrake and the firewyrm) deal energy damage, typically fire damage. In those cases, the type of energy damage is listed instead.

Crew: This column gives the number of creatures needed to properly use the siege engine, assuming Medium creatures. Some siege engines can be used with a smaller crew, but there are usually consequences such as slower aiming, firing, or movement.

Aim: This column gives the number of full-round actions (or move actions if the crew leader has the Master Siege Engineer feat) required to aim a siege engine. If the siege engine is being controlled by less than its normal crew complement, the number of actions it takes for the crew to aim the siege engine is doubled.

Load: This column gives the number of full-round actions (or move actions if the crew leader has the Master Siege Engineer feat) required to load a siege engine.

Speed: This is how fast the siege engine can be moved with move actions made by its entire crew.

Ranged Siege Engines

Ranged siege engines assault structures and people from a distance, by propelling ammunition in some fashion. Siege engines hurl massive projectiles in one of two ways: direct fire or indirect fire. Both take a number of actions to load or aim, and the basic rules are described below.

Load Ammunition: In order for a ranged siege engine to fire, it needs to be loaded with ammunition. Loading ammunition takes a number of full-round actions depending on the siege engine (this time can be reduced to move actions if the crew leader has the Master Siege Engineer feat.

Aiming a Siege Engine: Ranged siege engines must be aimed in order to attack a desired target (in the case of direct-fire siege engines) or square (in the case of indirect-fire siege engines). Aiming takes a number of full-round actions (or move actions if the crew leader has the Master Siege Engineer feat, with the number depending on the specific siege engine. Aiming a siege engine with a diminished crew doubles the amount of time it takes to aim the siege engine. Each time a new target or square is chosen as the target of a siege engine’s attack, that engine must be aimed anew.

Direct-Fire Ranged Siege Engines: Direct-fire weapons launch their projectiles on a relatively flat trajectory, allowing them to more easily target creatures or pummel barriers directly in front of them. A direct-fire weapon uses a normal attack roll, with the normal penalty for nonproficient use. In addition, a direct-fire weapon takes a –2 attack roll penalty per size category that the weapon is larger than the creature aiming it. Creatures that have ranks in Knowledge (engineering) or use a targeting platform (see below) are not adversely affected by their size when firing direct-fire ranged siege engines. Sheer manpower can also reduce the penalties for size. Increasing the crew of these weapons by 1 or more can reduce the attack roll penalty for creature size: as long as an extra crew member is no smaller than three size categories smaller than the direct-fire weapon, it can reduce the penalty due to the aiming creature’s size by 2. For example, a Huge ballista fired by a Medium creature that is part of a crew of two (the creature aiming the ballista and someone to help position it) takes only a –2 penalty on attack rolls.

Indirect-Fire Ranged Siege Engines: Indirect-fire weapons launch projectiles in high arcs toward their targets. They typically lob heavier missiles and payloads than direct-fire weapons, but they are harder to aim accurately. Indirect weapons can bypass many forms of fortification, delivering their payloads of solid shot, scatter shot, or even disease-ridden offal to targets beyond the walls of castles. They can also be used to batter fortifications where they are most vulnerable, arcing down on towers and walls, crushing them with the weight of stone or raining down smaller projectiles on a wall’s defenders. Indirect-fire weapons use a targeting mechanic similar to that described for catapults, hereafter referred to as an indirect attack. The following is an update to those rules.

Indirect Attack: To fire an indirect-fire ranged siege engine, the crew leader makes a targeting check against the DC of the siege engine. This check uses his base attack bonus, his Intelligence modifier (if not trained in Knowledge [engineering]) or Knowledge (engineering) skill modifier (if trained in that skill), any penalty for not being proficient in the siege engine, and the appropriate modifiers from Table: Indirect Attack Check Modifiers. If the check succeeds, the ammunition of the indirect attack hits the square the siege engine was aimed at, dealing the indicated damage or effect to any object or creature within the area of its attack. Creatures may get a saving throw to limit the effect of the attack; this is typically based on the type of ammunition used.

If the attack misses the intended square, roll 1d8 to determine in what direction the shot veers. A roll of 1 indicates the ammunition falls short (toward the siege engine), with rolls of 2 through 8 counting squares clockwise around the target square. Roll 1d4 for every range increment at which the attack was made (1d4 if the target square is within the engine’s first range increment, 2d4 if the target square is within the second range increment, and so on). The total is the number of squares by which the attack misses, with the direction in which the squares are counted determined by the d8 roll. The ammunition deals its damage and any other effects in the square it lands on.

Siege Weapon Descriptions

The following are siege weapon descriptions.

Ballista: Resembling a massive crossbow, a ballista’s power is provided by twisted skeins of animal sinew used as torsion springs driving a pair of adjustable arms. A cord attached to both arms is winched back and a projectile is loaded into a grooved slider for release. Ballistae are direct-fire weapons.

Light: This common type of ballista, also called an arbalest or scorpion, is size Large, maneuverable, and often mounted atop towers or even vehicles. Light ballistae have a hardness of 5 and 50 hit points. Light ballista bolts cost 10 gp each and weigh 10 pounds.

Heavy: These Huge-sized siege engines are commonly used as castle defenses, as well as on large warships. Heavy ballistae have a hardness of 5 and 100 hit points. Heavy ballista bolts cost 30 gp and weigh 20 pounds each.

Gate Breaker: This massive ballista fires specially weighted quarrels with blunt metal tips. These are used as long-range battering rams, shot at walls or the gates of castles. When they hit a wooden structure, they have a critical range of 19–20/×3. Gate breaker ballistae have a hardness of 5 and 200 hit points. Gate breaker ballista bolts cost 50 gp and weigh 30 pounds each.

Bombard: Resembling either large cauldrons or more traditional cannons, these firearms lob their ammunition in an arc in order to deliver their deadly payloads over troops or castle walls. Bombards are normally fired indirectly, but can also be fired as direct-fire siege engines. When they are used for direct fire, they take a –4 penalty on attack rolls and have their range increment halved, but do not have a minimum range. Like all firearms, bombards do not suffer mishaps, but instead have a misfire chance.

Light: These bombards resemble cauldrons attached to swivels. Often they are mounted into the ground or into the stone of castle walls because of the mighty power of their recoil. The targeting DC of a light bombard is 15. A light bombard has a base misfire range of 1–2 (10 feet). Light bombards have a hardness of 10 and 70 hit points. Light bombard balls cost 30 gp each and weigh 25 pounds.

Standard: These bombards feature the greatest diversity of forms. Many take the cauldron shape of the light bombard, but they may also take the forms of more traditional cannons, albeit featuring stabilizing mechanisms that allow them to fire at a much steeper incline. The targeting DC of a standard bombard is 20. A standard bombard has a misfire range of 1–2 (20 feet). Standard bombards have a hardness of 10 and 140 hit points. Standard bombard balls cost 35 gp each and weigh 30 pounds.

Heavy: These massive siege engines are often fixed to positions on high hilltops or atop massive keeps, raining death down on a valley or strait. Often these firearms come in two pieces connected by a screw mechanism. The bombard is unscrewed to be loaded, and then the main part of the muzzle is screwed back on to the barrel section in order to be fired. Heavy bombards are too large and powerful to mount on vehicles. The targeting DC of a heavy bombard is 25. A heavy bombard has a misfire range of 1–2 (30 feet). Heavy bombards have a hardness of 10 and 280 hit points. Heavy bombard balls cost 45 gp each and weigh 50 pounds.

Cannon: Cannons are crafted of metal—some are cast in one piece, others welded with iron bands—and mounted either in the ground or on wooden frames. Cannons use black powder to propel their projectiles with great force. A cannon has a misfire range of 1 (20 feet). Cannons have a hardness of 10 and 70 hit points. Cannon balls cost 30 gp each and weigh 25 pounds.

Catapult: Catapults are stone-throwing siege engines powered by winched arms that run through torsion skeins, and hold their payload in a cup that swings up and over the weapon when released. Catapults can hurl a variety of different types of ammunition (the damage given is for stone projectiles; other types of ammunition can be found later in this chapter). They are indirect-fire siege engines. Light: These catapults are Large and often mounted on wheels. The targeting DC of a light catapult is 15. Light catapults have a hardness of 5 and 50 hit points. Light catapult stones cost 10 gp and weigh 50 pounds each.

Standard: These Huge siege engines are too large to be transported to the battlefield in one piece, and require assembly. They typically hurl large stones indirectly at a target (targeting DC 20). Standard catapults have a hardness of 5 and 100 hit points. Standard catapult stones cost 15 gp and weigh 75 pounds each.

Heavy: These Gargantuan siege engines are too large to be transported to the battlefield in one piece, and require assembly. They typically hurl large stones indirectly at a target (targeting DC 25). Heavy catapults have a hardness of 5 and 200 hit points. Heavy catapult stones cost 25 gp and weigh 90 pounds each.

Fiend’s Mouth Cannon: These massive cannons are usually crafted in multiple pieces, and sometimes feature the heads of demons, devils, or other fiends at their mouths. Like normal canons, they propel their projectiles with great force. A fiend’s mouth cannon has a misfire range of 1 (30 ft.). Fiend’s mouth canons have a hardness of 10 and 140 hit points. Fiend’s mouth cannon balls cost 45 gp and weigh 30 pounds each.

Firedrake: These large siege engines are typically wheeled or attached to vehicles that can transport them to the battlefield. This apparatus fires gouts of alchemist’s fire in either a 60-foot line or a 30-foot cone (siege crew leader’s choice). Targets in the area take 6d6 points of fire damage (DC 15 Reflex save halves); those who fail their saves also catch on fire. A firedrake with the broken condition that suffers a further mishap explodes, dealing its damage to all creatures within a 20-foot blast (DC 15 Reflex save halves). Firedrakes have a hardness of 10 and 70 hit points. One use of firedrake ammunition costs 200 gp and weighs 20 pounds.

Firewyrm: This siege engine is a larger version of the firedrake. A firewyrm is too large to be transported to the battlefield in one piece and must be assembled once the component parts reach the battlefield. A firewyrm fires its gout of flame in either a 120-foot line or a 60-foot cone (crew leader’s choice). Targets in the area take 6d6 points of fire damage (DC 20 Reflex save halves). Those who fail their saves catch on fire. A firewyrm with the broken condition that suffers a further mishap explodes, dealing its damage to all creatures within a 30-foot blast (DC 20 Reflex save halves). Firewyrms have a hardness of 10 and 140 hit points. One use of firewyrm ammunition costs 400 gp and weighs 40 pounds.

Springal: A springal uses a torsion-cranked composite paddle to strike a firing rack containing multiple arrows or black-powder-propelled rockets, which rain down in an arc over a burst area. Springals are indirect-fire weapons that affect an area centered on the target square.

Arrow: This springal propels a group of arrows that rains down on the targeted square and in a 15-foot burst around that square. One use of arrow springal ammunition costs 20 gp and weighs 10 pounds.

Rocket: This highly volatile springal propels a group of black-powder rockets that rain down on the targeted square and in a 15-foot burst around the area. If the rocket springal misfires, it explodes, dealing its damage in a 20-foot blast around the springal. This explosion destroys the rocket springal. One use of rocket springal ammunition costs 500 gp and weighs 30 pounds.

Trebuchet: Trebuchets are similar in form to catapults, with the payload placed into a basket, cup, or sling at the end of a long lever, and a counterweight (often with crew or animals pulling attached ropes) close to the fulcrum. The leverage imparted by a trebuchet allows it to hurl massive missiles that scatter to a number of squares around the target square based on the size of the trebuchet. Trebuchets are too bulky to move on wheels or vehicles and must be assembled on the battlefield. Trebuchets have a minimum range of 150 feet.

Light: These Large siege engines typically hurl large stones indirectly at a target (targeting DC 15). A light trebuchet’s ammunition scatters on contact, dealing full damage to the target square and half its damage to creatures and objects within 5 feet of the target square (creatures can make a DC 15 Reflex save to halve the damage again). Light trebuchets have a hardness of 5 and 50 hit points. One use of light trebuchet stones costs 15 gp and weighs 60 pounds.

Standard: These Huge siege engines typically hurl large stones indirectly at a target (targeting DC 20). A standard trebuchet’s ammunition scatters on contact, dealing full damage to the target square and half damage to creatures and objects within 15 feet of the target square (creatures can make a DC 20 Reflex save to halve the damage again). Standard trebuchets have a hardness of 5 and 100 hit points. One use of standard trebuchet stones costs 30 gp and weighs 110 pounds.

Heavy: These Gargantuan siege engines typically hurl large stones indirectly at a target (targeting DC 25). A heavy trebuchet’s ammunition scatters on contact, dealing full damage to the target square and half its damage to creatures and objects within 30 feet of the target square (creatures can make a DC 25 Reflex save to halve the damage again). Heavy trebuchets have a hardness of 5 and 200 hit points. One use of heavy trebuchet stones costs 40 gp and weighs 120 pounds.

Table: Indirect Attack Check Modifiers
Condition Modifier
No line of sight to target square –6
Successive shots (crew can see where most recent miss landed) Cumulative +2 per previous miss (maximum +10)
Successive shots (crew can’t see where most recent missed Cumulative +1 per previous miss (maximum +5) shot landed, but observer is providing feedback)
Successive shots after a hit +10
Table: Ranged Siege Engines
Direct Fire Engines
Large Cost Dmg Critical Range Type1 Crew Aim Load Speed Source
Ballista, light 500 gp
3d8 19-20/x2 120 ft. P 1 0 2 10 ft. PRG:UC
Cannon 6,000 gp 6d6 x4 100 ft. B and P 2 1 3 10 ft. PRG:UC
Huge Cost Dmg Critical Range Type1 Crew Aim Load Speed Source
Ballista, heavy 800 gp 4d8 19-20/x2 180 ft. P 3 2 3 0 ft. PRG:UC
Cannon, fiend’s mouth 9,000 gp 8d6 x4 150 ft. B and P 3 1 3 0 ft. PRG:UC
Firedrake 4,000 gp 6d6 fire 3 2 5 10 ft. PRG:UC
Manticore’s tail 1,000 gp 3d8 19–20/×2 60-ft. cone P 3 0 4 10 ft. PPC:OrcHordes
Gargantuan Cost Dmg Critical Range Type1 Crew Aim Load Speed Source
Ballista, gate breaker 1,200 gp 6d8 19-20/x2 100 ft. B 5 3 5 0 ft. PRG:UC
Firewyrm 6,000 gp 6d6 fire 5 2 6 0 ft. PRG:UC
Indirect Fire Engines
Large Cost Dmg Critical Range Type1 Crew Aim Load Speed Source
Bombard, light 6,000 gp 5d6 x4 100 ft.
(50 ft. min.)
B and P 2 1 3 10 ft. PRG:UC
Catapult, light 550 gp 4d6 x2 150 ft.
(50 ft. min.)
B 2 2 3 10 ft. PRG:UC
Trebuchet, light 800 gp 4d6 x2 200 ft.
(100 ft. min.)
B 3 2 3 0 ft. PRG:UC
Huge Cost Dmg Critical Range Type1 Crew Aim Load Speed Source
Bombard, standard 8,000 gp 7d6 x4 150 ft.
(100 ft. min.)
B and P 2 1 3 0 ft. PRG:UC
Catapult, standard 800 gp 6d6 x2 200 ft.
(100 ft. min.)
B 3 2 3 0 ft. PRG:UC
Springal, arrow 1,000 gp 3d8 x3 100 ft.
(50 ft. min.)
P 3 2 3 0 ft. PRG:UC
Springal, rocket 6,000 gp 3d10 x4 100 ft.
(50 ft. min.)
fire 3 2 3 0 ft. PRG:UC
Trebuchet, standard 1,000 gp 6d6 x2 300 ft.
(150 ft. min.)
B 4 2 3 0 ft. PRG:UC
Gargantuan Cost Dmg Critical Range Type1 Crew Aim Load Speed Source
Bombard, heavy 16,000 gp 9d6 x4 200 ft.
(100 ft. min.)
B and P 4 3 5 0 ft. PRG:UC
Catapult, heavy 1,000 gp 8d6 x2 300 ft.
(100 ft. min.)
B 4 3 3 0 ft. PRG:UC
Trebuchet, heavy 1,500 gp 8d6 x2 400 ft.
(200 ft. min.)
B 4 3 3 0 ft. PRG:UC

A weapon with two types is both types if the entry specifies “and.”

Special Siege Engine Ammunition

The following kinds of ammunition can be used either in select types of indirect-fire siege engines, or with cannons. The ammunition description specifies which types of siege engines use the special ammunition. The costs and weights on Table: Special Siege Engine Ammunition are for individual uses of special ammunition.

Table: Special Siege Engine Ammunition
Ammunition Cost Weight Source
Alchemical fire 200 gp 10 lbs. PRG:UC
Blast shot 30 gp 25 lbs. PRG:UC
Bomb 600 gp 30 lbs. PRG:UC
Chain shot 50 gp 30 lbs. PRG:UC
Defoliant shot 300 gp
20 lbs.
PCS:OrcHordes
Entangling bolt 50 gp
25 lbs.
PCS:OrcHordes
Liquid ice 400 gp 20 lbs. PRG:UC
Plague bundle 80 gp 20 lbs. PRG:UC
Rockwasp bomb 2,000 gp
100 lbs.
PCS:OrcHordes
Smoke shot 250 gp 20 lbs. PRG:UC

Alchemical Fire: This hard, ceramic canister of alchemist’s fire can be used as ammunition in catapults and trebuchets. When it hits its target square, it deals 4d6 points of fire damage to each creature and wooden structure within 5 feet of the target space, and each creature must make a DC 20 Reflex saving throw or catch on fire (wooden objects automatically catch on fire). Every creature and wooden object within the area between 5 and 30 feet of the target space must make a DC 20 Reflex saving throw or take half the fire damage, but they do not catch on fire. On a siege engine mishap, this ammunition explodes before it is launched, dealing its damage to the siege engine and all nearby creatures and wooden objects as if one of the spaces of the siege engine (crew leader’s choice) were the target square. This alchemical fire ignores the hardness of wooden objects.

Blast Shot: Instead of a single hard ball, this ammunition is a bundle of large pellets, balls, or pieces of scrap metal, propelled a short distance by black powder and attacking all creatures and objects within an area. Both cannons and fiend’s mouth cannons can fire this kind of ammunition. When such a siege engine fires this ammunition, it hits every creature and object within a 30-foot-cone burst. The siege engine makes attack rolls against each creature and unattended object in the burst. It must miss every creature or target to misfire, and a misfire generates the normal effect. It deals its normal damage on a hit, but does not ignore the hardness of objects.

Bomb: A bomb is a metal canister filled with metal balls and black powder that can be used as ammunition in catapults and trebuchets or carried by two Medium creatures or one Large creature to its destination. A bomb either explodes on impact (if fired from a catapult or trebuchet, or within 3 rounds of a fuse being lit if carried). When it explodes, it deals 6d6 points of piercing and bludgeoning damage to all creatures and objects within 30 feet of the target square. On a siege engine mishap, this ammunition explodes before it is launched, dealing its damage to the siege engine and all nearby creatures and wooden objects as if one of the spaces of the siege engine (crew leader’s choice) were the target square. It ignores the hardness of wood and stone.

Chain Shot: This siege engine firearm ammunition can be loaded in a cannon or a fiend’s mouth cannon. It is especially good at tearing through sails and dirigibles (see Vehicles), dealing double its normal damage to those forms of propulsion. When fired at a creature, on a hit, the creature must succeed at a DC 20 Fortitude saving throw or be knocked prone.

Defoliant Shot: When used as ammunition in a catapult or trebuchet, this ceramic canister releases a mist of defoliant on impact. When it hits the target square, it deals 2d6 points of damage to any creature in that space. Plant creatures within 30 feet of the target square take an additional 4d6 points of damage. A successful DC 20 Fortitude saving throw halves this additional damage. Plant creatures within 5 feet of the target space that fail their saving throws also take 1d4 points of Strength damage and 1d4 points of Constitution damage. The defoliant also kills vegetation within 30 feet of the target square. On a siege engine mishap, this ammunition explodes before it’s launched, dealing its damage to the siege engine and all nearby plant creatures as if one of the spaces of the siege engine (crew leader’s choice) were the target square. Source PCS:OrcHordes

Entangling Bolt: When launched from a ballista, this specialized bolt unfurls into a large net. An attack with entangling ammunition is a ranged touch attack, but it’s only effective within one range increment. If it hits, the target is entangled, but the attack deals no damage. An entangled creature can escape with a successful DC 20 Escape Artist check (a full-round action). The net has 5 hit points and can be burst with a successful DC 25 Strength check (also a full-round action). Entangling ammunition is useful only against creatures within one size category of the firing ballista. Source PCS:Belkzen, Hold of the Orc Hordes

Liquid Ice: This hard, ceramic canister filled with alchemical liquid ice can be used as ammunition in catapults and trebuchets. When it hits its target square, it deals 4d6 points of cold damage to each creature within 5 feet of the targeting space, and each creature must make a DC 20 Fortitude save or become entangled for 1 round. Every creature within the area between 5 and 30 feet of the target space must make a DC 20 Fortitude saving throw or take half damage. On a siege engine mishap, this ammunition explodes before it is launched, dealing its damage to all nearby creatures as if one of the spaces of the siege engine (crew leader’s choice) were the target square.

Plague Bundle: This hard, ceramic canister is filled with a noxious mass of diseased carrion and offal that can be used as ammunition for a catapult or a trebuchet. It deals only half damage, but every creature hit by it is exposed to filth fever. A GM might allow a plague bundle to inflict other diseases.

Rockwasp Bomb: Usable in catapults and trebuchets, this ammunition consists of a wooden crate packed with wax globes, from which a faint buzzing sound emanates. Visible as a dark shape at the center of each globe is a rat-sized hornet known as a rockwasp. The alchemical wax keeps the wasps immobilized, while tiny air holes allow them to breath. This ammunition deals only half damage, but releases a wasp swarm—two wasp swarms if used for a heavy catapult or heavy trebuchet. The wasps attack for 1 minute before dispersing. On a siege engine mishap, the wasps escape before the ammunition is launched. Source PCS:Belkzen, Hold of the Orc Hordes

Smoke Shot: This hard ceramic sphere contains two alchemical substances separated by a thin barrier, much like a smoke pellet in larger form. When it hits the targeting space, it deals 2d6 points of damage to any creature in that space, and the substances mingle and then create an area of foul but harmless yellow smoke radiating 30 feet from the target square. Treat the effect as a fog cloud spell. On a siege engine mishap, the ammunition explodes before it is launched. Its effect is centered on one of the spaces of the siege engine (crew leader’s choice).

Close Assault Siege Engines

While most siege engines attack at range, some are used up close to directly undermine defenses, batter through them, or otherwise bypass them. Some close assault weapons are not even weapons at all, but instead provide means for assault forces to protect themselves or circumvent fortifications without destroying them.

Table: Close Assault Siege Engines
Bridge, assault
Size Cost Dmg Critical Type1 Crew Load* Speed Source
Large 1 gp PRG:UC
Huge 10 gp PRG:UC
Gargantuan 50 gp PRG:UC
Colossal 250 gp PRG:UC
Corvus
Size Cost Dmg Critical Type1 Crew Load* Speed Source
Corvus 100 gp 1 Special PRG:UC
Crushing wheel
Size Cost Dmg Critical Type1 Crew Load* Speed Source
Large 500 gp 4d6 B 4 15 ft. PCS:OrcHordes
Harvester
Size Cost Dmg Critical Type1 Crew Load* Speed Source
Large 800 gp 2d8 ×4 S 4 15 ft. PCS:OrcHordes
Earthmaul
Size Cost Dmg Critical Type1 Crew Load* Speed Source
Huge 1,000 gp 6d6 B 3 3 10 ft. PCS:OrcHordes
Gallery
Size Cost Dmg Critical Type1 Crew Load* Speed Source
Large 250 gp 3 15 ft. PRG:UC
Huge 500 gp 6 15 ft. PRG:UC
Gargantuan 1,000 gp 9 15 ft. PRG:UC
Colossal 2,000 gp 18 15 ft. PRG:UC
Ladder, escalade
Size Cost Dmg Critical Type1 Crew Load* Speed Source
Large 5 gp 2 as crew speed PRG:UC
Huge 10 gp 4 as crew speed PRG:UC
Gargantuan 50 gp 6 as crew speed PRG:UC
Colossal 250 gp 8 as crew speed PRG:UC
Ram
Size Cost Dmg Critical Type1 Crew Load* Speed Source
Large 500 gp 2d6 x3 B 5 15 ft. PRG:UC
Huge 1,000 gp 3d6 x3 B 10 15 ft. PRG:UC
Gargantuan 2,000 gp 6d6 x3 B 20 15 ft. PRG:UC
Colossal 5,000 gp 10d6 x3 B 40 15 ft. PRG:UC
Siege tower
Size Cost Dmg Critical Type1 Crew Load* Speed Source
Large 1,000 gp 6 15 ft. PRG:UC
Huge 2,000 gp 12 15 ft. PRG:UC
Gargantuan 5,000 gp 24 15 ft. PRG:UC
Colossal 10,000 gp 48 15 ft. PRG:UC

Bridge, Assault: An assault bridge is used to span a ditch, moat, or other gap. Raising an assault bridge requires one full-round action per 5 feet of length; up to four creatures may cooperate to raise a bridge. The time required is doubled for each size category that the bridge is larger than the creatures raising it. Large assault bridges have 40 hit points, Huge ones have 60 hit points, Gargantuan ones have 160 hit points, and Colossal ones have 240 hit points.

Table: Bridges and Escalade Ladders
Size Width Length/Height
Large 5 ft. 20 ft.
Huge 5 ft. 30 ft.
Gargantuan 10 ft. 40 ft.
Colossal 10 ft. 60 ft.

Corvus: A corvus is a boarding device that features a hinged counterweight system for mounting a bridge vertically on a siege tower or a vehicle, with a hooked end to grab onto a target vehicle or structure. A corvus is usually 10 feet wide and 15 feet long. It has a hardness of 5 and 10 hit points per square. Using a corvus requires a DC 10 Profession (siege engineer) check as a full-round action; if the check fails, the corvus fails to catch on the target and must be reset (a full-round action). A corvus mounted on a vehicle can target another moving vehicle (see Vehicles). Doing so requires an opposed driving check to get the corvus into the correct position, which is within the length of the corvus and adjacent to the other vehicle. Once a corvus is attached, it takes a Strength check as a full-round action to dislodge the corvus. Alternatively, if the corvus is attached to a vehicle, either vehicle driver can make a driving check as a standard action to dislodge the corvus (a check that succeeds by 5 or more destroys the corvus). The base DC for either of these checks is 15, and the DC increases by 5 for every Small or Medium creature currently standing on the corvus. If a corvus is disengaged while creatures are standing on it, those creatures must make a DC 15 Reflex saving throw or fall. Succeeding at the saving throw allows them to move to the nearest area of safe ground, but such movement provokes attacks of opportunity. A corvus cannot be armored.

Crushing Wheel: The bulk of this weapon is a steel roller nearly 10 feet wide. Handles or a harness project from the axle, allowing four orcs or one Large beast to push the crushing wheel from behind. As a full-round action, its crew can roll the crushing wheel over creatures in front of it. This functions as the trample monster ability except as noted here. Creatures that are overrun fall prone and take 4d6 points of damage. Targets that succeed at a DC 15 Reflex saving throw take only half damage and avoid falling prone. A crushing wheel has a hardness of 10 and 100 hit points. Source Hold of the Orc Hordes

Earthmaul: This war machine is fitted with an enormous hammer. When dropped into the horizontal position, it functions like a sideways-mounted catapult, and is capable of clearing wide swaths of enemies. Although it doesn’t use ammunition, the earthmaul must effectively be reloaded by winding the torsion. When the earthmaul is activated, creatures on the ground in a 15-foot cone take 6d6 points of damage, are knocked 10 feet in the direction of the swing, and fall prone. A successful DC 20 Reflex saving throw halves the damage and negates the additional effects. An earthmaul has a hardness of 5 and 100 hit points. Source Hold of the Orc Hordes

Gallery: A mobile temporary defense, a gallery is similar to a building made of hide or wood. Most are of flimsy construction, but rare examples are more stoutly built (use the rules for giving siege engines armor, and adjust AC, hardness, and hit points accordingly). Galleries are almost always a single section of movable “wall” plus another section that acts as the “roof.” (Galleries made to house battering rams are an exception, and typically have two joined wall sections and roof sections.) Because a gallery is partially open, it does not provide the same cover as a normal building: a creature inside a gallery gains cover if it is the same size as the gallery, improved cover if it is one size smaller, and total cover if it is two or more sizes smaller. Galleries are sized like creatures—a Large gallery protects the same space as a Large creature, and so on.

Wooden galleries can be moved on rollers at a speed of 10 feet with their full crew, or 5 feet with at least half the required crew. Galleries have a base speed of 15 feet (or 10 feet if protected with medium or heavy armor).

Galleries have a hardness of 5, and hit points based on their size. A Large gallery has 30 hit points, a Huge one has 120 hit points, a Gargantuan one has 320 hit points, and a colossal one has 625 hit points.

Harvester: A variety of scythe-like blades extend from two sides of this wheeled machine. When it’s pulled—typically by an aurochs or enslaved giants—the wheels’ rotation causes the blades to slash indiscriminately. Each round the harvester moves, it makes a melee attack with a +10 modifier against any adjacent creature it passes; it deals 2d8 points of damage to those it hits. Multiple harvesters can be strung together. The crew required for a train of harvesters is equal to the total crew of the individual machines. Adjacent creatures are attacked by each individual harvester that passes them. A harvester has a hardness of 5 and 50 hit points. Source Hold of the Orc Hordes

Ladder, Escalade: Escalade ladders have spiked bases for stability, and the upper 5 feet are metal-shod, with hardness 10 and 20 hit points. The remainder of the ladder is wooden and has hardness 5 and hit points based on its size. Large escalade ladders have 20 hit points, Huge ones have 30 hit points, Gargantuan ones have 80 hit points, and Colossal ones have 120 hit points. Escalade ladders cannot be armored.

Manticore’s Tail: This massive ballista fires a dozen or more bolts at once in a devastating rain of steel that deals 3d8 points of damage. The crew leader makes a separate attack roll with a –2 penalty against each creature and object within a 60-foot cone, ignoring concealment. Confirm any critical threats separately. This weapon has a mishap only if the first attack roll is a mishap. A manticore’s tail has a hardness of 5 and 100 hit points. Ammunition for one use of the manticore’s tail costs 120 gp and weighs 120 pounds. Source Hold of the Orc Hordes

Rams: The most basic close assault weapons are iron-shod logs carried by one or more creatures to combine their strength. A ram can be used to deal damage or to make a Strength check against the target’s break DC.

Ramming Charge: Rams require momentum to be effective. All creatures using the ram must use the charge action to gain its full effect. Creatures not wishing to charge may make a ram attack as a full-round action, taking a –4 penalty on attack and damage rolls and Strength checks with the ram.

Breaking: The crew leader makes a Strength check with a +2 bonus, adding +2 for each member of the crew (or equivalent number of larger creatures; see Crew) assisting. The ram also provides a +4 bonus per size category above Medium.

Damage: The crew leader makes an attack roll with a –4 nonproficiency penalty. A hit deals the listed damage, plus the Strength modifiers of the crew leader and all members of the crew, regardless of their size.

Improvised Ram: Any tree, log, or timber can be used as a ram with a –4 penalty on attack and damage rolls and Strength checks.

Pick: A ram with a pick head grants a +2 circumstance bonus on Strength checks and attack and damage rolls made against stone structures.

Screw: A ram with a screw head grants a +2 circumstance bonus on Strength checks and attack and damage rolls made against earthen structures.

Gallery Ram: This is a ram suspended from chains or ropes within a gallery. A gallery ram does not require a charge action for full momentum. In addition, adding tethers to the back end of the ram allows four additional crew members to assist in using the ram.

Hit Points: Rams have a hardness of 5 and hit points based on their size. A Large ram has 30 hit points, a Huge one has 120 hit points, a Gargantuan one has 320 hit points, and a Colossal one has 625 hit points. Improvised rams have half the normal hit points.

Siege Tower: A wooden gallery of stout construction, a siege tower consists of a tall protective shell with a roof section. The lower story of the tower contains the crew members who propel the tower, and provides total cover to those within. A siege tower with the broken condition moves at half speed. If a siege tower is destroyed, the entire tower collapses. Treat this as a cave-in.

The upper section of a siege tower provides improved cover for a number of soldiers (see Crew) and may have pierced walls allowing creatures to fire ranged weapons out the sides. The roof section may have a battlement and may mount a siege engine of the siege tower’s size or smaller and a corvus. Siege towers have a base speed of 15 (or 10 feet if protected with medium or heavy armor).

Siege towers have a hardness of 5, and hit points based on their size. A Large siege tower has 60 hit points, a Huge one has 240 hit points, a Gargantuan one has 640 hit points, and a Colossal one has 1,250 hit points.

Table: Siege Tower Complement
Size Soldiers
Large 5
Huge 20
Gargantuan 50
Colossal 200

Structure Hardness and hit points

While armies can use siege weapons against troops, usually the goal of a siege engine is to demoralize foes and pound their structures to rubble. The following rules give the statistics for various buildings and barriers that are often the targets of siege engine attacks. They are split up into three different categories: buildings, gates, and walls.

When any of these structures gain the broken condition, their hardness is halved, along with any other effects of the broken condition.

Buildings

Buildings are sizable structures with many hit points and very poor ACs (a Large building is AC 4, a Huge building is AC 3, and a Gargantuan or larger building is AC 0). When a building is reduced to half its hit points, it is broken—it still stands, but only partially. It can be easily entered, and for all intents and purposes it has been breached. Reducing a building to 0 hit points completely destroys that building. Creatures inside the building suffer the effects of a cave-in.

All these building statistics assume that the structure’s inside is somewhat hollow but sturdily built, with enough space for its occupants to walk around inside. Flimsy buildings have half the hit points of the buildings detailed in Table: Buildings. Buildings can be magically treated, like dungeon walls and doors can. Doing so doubles their hardness and hit points. Magically treating a building costs 5,000 gp for a Large building, 10,000 gp for a Huge building, 20,000 gp for a Gargantuan building, and 40,000 gp for a Colossal building. A spellcaster with the Craft Magic Arms and Armor feat can magically treat buildings.

For larger buildings, put together multiple buildings of these sizes and add the hit points together.

Table: Buildings
Material Hardness Hit Points
Large Huge Gargantuan Colossal
Wood 5 120 270 960 3,240
Stone 8 200 450 1,600 5,400
Iron or steel 10 400 900 3.200 10,800
Adamantine 20 560 1,260 4,480 15,120

Gates

Gates serve as the entrances and exits to fortified structures, and are typically the weakest spots in any fortification’s defenses. Gates are at least Large, but can be as large as Colossal. It typically takes three full-round actions to open or close a Large gate (up to three creatures can work together to close a Large gate as a full-round action), and larger gates typically take at least a minute to close or open. Gates have ACs based on their size (a Large gate is AC 4, a Huge gate is AC 3, and a Gargantuan or larger gate is AC 0).

Gates can be magically treated. Doing so doubles the hardness and hit points. Magically treating a gate costs 2,000 gp for a Large gate, 4,000 gp for a Huge gate, 8,000 gp for a Gargantuan gate, and 16,000 gp for a Colossal gate. A spellcaster with the Craft Magic Arms and Armor feat can magically treat gates.

Gates can be attacked and damaged, or they can become broken (as the condition) with a successful Strength check, usually as a result of ramming. When a gate gains the broken condition, it is effectively breached, and can be moved through as if it were an opening one size smaller.

Table: Gates
Material Break DC1 Hardness Hit Points
Large Huge Gargantuan Colossal
Wood 35 5 60 135 240 540
Stone 38 8 100 225 400 900
Iron or steel 24 10 200 500 800 1,800
Adamantine 48 20 280 630 1,120 2,520

1 The DC assumes the gate is size Large and is barred and locked. Huge doors increase the break DC by 5, Colossal doors increase the DC by 10, and Gargantuan doors increase the DC by 15. Arcane lock increases the DC by 10.

Walls

The walls that guard castles and cities are sturdy fortifications, usually constructed in a series of 5-foot squares. A square of wall has an AC of 5, and hardness and hit points equal to its type.

Squares of walls can be magically treated. Doing so doubles the hardness and hit points. Magically treating wall squares costs 500 gp per wall square. A spellcaster with the Craft Magic Arms and Armor feat can magically treat walls.

When a wall gains the broken condition, its hardness is halved, but the wall is not breached. Only destroying a section of wall allows it to become breached. When a square of wall is breached, any sections directly above it fall onto the missing section of walls. Doing this reduces the falling wall section to half its current hit point total –1, which applies the broken condition to that square of wall.

Table: Walls
Material Hardness Hit Points per
5-Foot Square
Wood 5 30
Stone 8 45
Iron or steel 10 90
Adamantine 20 120
3rd Party Publisher Siege Engines

Siege engines that have been added to d20pfsrd.com from various 3rd Party Publisher sources can be found at the link below.

3rd Party Siege Engines

Section 15: Copyright Notice – Pathfinder Roleplaying Game Ultimate Combat

Pathfinder Roleplaying Game Ultimate Combat. © 2011, Paizo Publishing, LLC; Authors: Jason Bulmahn, Tim Hitchcock, Colin McComb, Rob McCreary, Jason Nelson, Stephen Radney-MacFarland, Sean K Reynolds, Owen K.C. Stephens, and Russ Taylor.